The development of this clever app started from one teen's dream to keep his grandfather safe.

The SafeWander app and button sensor is the world’s first wearable sensor that sends an alert to a caregiver’s mobile device when a loved one or a patient gets up from a bed or chair, even if the caregiver is far away.

Kenneth Shinozuka was four years old when his beloved grandfather, Deming, started to show signs of Alzheimer's disease. Just a few years later, Deming started wandering in the middle of the night, and after an incident in which he wandered onto a freeway, Kenneth knew something needed to be done.

Kenneth tried to find a device that would quickly alert him when his grandfather wandered out of bed, but to no avail. He then decided to take matters into his own hands and created a sensor that reacts to an upright movement. The teenager has achieved international fame and corporate sponsorship since coming up with the prototype device.

The button-shaped sensor can be easily and quickly attached to any garment the person is wearing.

The second the patient sits up in bed and wanders off, the sensor sends a signal to a mobile phone to alert caregivers or family members of wandering.

With millions of people affected by Alzheimer's throughout the world, it's not hard to see that Kenneth's invention has a lot of potential to help people.

Research for the US Alzheimer's Association estimated the prevalence of wandering as about 60 percent. If a person is not found within 24 hours, up to half of the individuals who wander will suffer serious injury or death, they have found.

The SafeWander app will relieve some of the burdens that caregivers experience in caring for Alzheimer's and dementia patients, which was one of Kenneth's goals after having seen what his aunt went through to care for his grandfather.

"My grandfather has lost the capability to eat by himself, to walk by himself, to write and to read. He can barely speak anymore. So it's very hard. It's also very hard for my aunt, his primary caregiver, since she's the one who has to take care of him all the time,” Kenneth said in a recent TV interview.

“The sensor is attached to my grandfather’s pyjamas and alerts my aunt when he gets out of bed, so she doesn’t have to continually wake up to check on him in the middle of the night.”